Field of Invention
The present invention relates to reducing non-local network traffic. More specifically, this invention relates to caching content in equipment at the premises of one or more end users.
Discussion of the Background
Content Delivery Networks (CDNs) have sprung up at the headends of most large internet service providers (ISPs) over the past 15 years or so. CDNs cache content (e.g., time sensitive content) from one or more content sources (e.g., central servers). Relative to the central servers, CDNs are strategically placed to be closer to the customer (i.e., end user). When an end user requests content that has been cached in a CDN, the CDN serves the content to the customer and eliminates the need for the content source to serve the content to the customer. The goal of CDNs is to make the customer's experience better providing content faster and more reliably than the content sources by themselves could.
FIG. 1 is a schematic diagram illustrating an example of a conventional data distribution system 100 in which modems 102 at customer premises receive content from a headend (i.e., master facility for receiving content signals for processing and distribution) 104. The system 100 may be, for example, a cable system in which the modems 102 are cable modems and in which the headend 104 includes a cable modem termination system (CMTS). The CMTS may provide high speed data services, such as cable Internet or voice over internet protocol (VOIP), to end users (e.g., subscribers or customers). In another example, the system 100 may be a digital subscriber line (DSL) system in which modems 102 are DSL modems and in which the headend 104 includes a DSL access multiplexer (DSLAM).
One or more CDN servers 106 of one or more CDNs may be connected (e.g., directly or through the internet 108) to the headend 104. The CDN servers 106 may cache content from one or more content sources (e.g., content servers) 110. The headend 104 may receive content from one or more of the CDN servers 106 and/or one or more of the content sources 110 through the internet 108. The headend 104 may provide content received from one or more CDN servers 106 and/or one or more content sources 110 to one or more customers via a non-local network 112.
A non-local network, such as non-local network 112, can best be defined relative to a local network (e.g., a local area network) that interconnects computers in a limited area such as a home, school, computer laboratory or office building and does not use leased telecommunication lines (i.e., telecommunication lines to which a service provider grants access in return for compensation). In contrast with local networks, non-local networks typically have lower data-transfer rates and larger geographic area and use leased telecommunication lines. The non-local network 112 may be, for example, a wide area network (WAN) or metropolitan area network (MAN). The non-local network 112 may be, for example, a broadband network, such as a hybrid fiber/coaxial (HFC) network, or a telephone network.
A customer receives and/or transmits information from/to non-local network 112 using equipment at the customer's premises (i.e., customer-premises equipment (CPE)), which may include the modem (e.g., cable modem or DSL modem) 102. The CPE may additionally include a firewall/router 114 (e.g., network address translation (NAT) router) and switch 116 and one or more computers 117, which may be connected over a local area network (in contrast to the non-local network leading up to the customer premises). The one or more computers 117 of the CPE may, for example, be located at a home, school, computer laboratory or office building.
FIG. 2 is a schematic diagram illustrating an example of a conventional modem 102 that is a conventional cable modem. The conventional cable modem may include a network interface (e.g., coaxial interface) 218, tuner 220, demodulator 222, media access control (MAC) controller 224, modulator 226, central processing unit (CPU) 228, network components 230 and an interface (e.g., Ethernet and/or USE interface) 232. The conventional cable modem receives data from and transmits data to non-local network 112 via network interface 218. The tuner 220 retrieves modulated data from a particular set of frequencies or channel(s) from the interface 218 and passes the modulated data to the demodulator 222, which demodulates the modulated data. The MAC controller 224 receives demodulated data from the demodulator 222, processes the demodulated data according to a MAC protocol and passes it to the CPU 228 and/or network components 230 for processing before being output on interface 232. Data received from interface 232 is processed by the network components 230 and/or CPU 228 before being processed according to the MAC protocol by MAC controller 224 and passed to the modulator 226, which modulates the data before transmitting it to the non-local network 112 via network interface 218.
Using the conventional system 100, requests for content are individually sent from each CPE (e.g., modem 102, firewall/router 114 and switch 116). Each request must traverse the entire non-local network 112. After a request reaches the one or more CDN servers 106, if the one or more CDN servers 106 has cached the requested content, the one or more CDN servers 106 transmits the requested content over the non-local network 112 to the individual CPE that requested the content. If the one or more CDN servers 106 has not cached the requested content, the request is forwarded to a content source 110 over the Internet transit network 108. The content source 110 then transmits the requested content over Internet transit network 108 and non-local network 112 to the individual CPE that requested the content. This procedure is repeated for each of the individual requests for content.
Previously, saturation points existed in the interconnects between the networks that make up the internet (i.e., backbones). However, today, backbone bandwidth is plentiful. Instead, the choke point of most internet traffic today exists in the “last mile” connections (i.e., the connections between the headend 104 and the modems 102 over the non-local network 112). In other words, internet traffic congestion issues today are “edge” related in the sense that the choke points are at the outer edges of the data distribution network.
Cable modem technology is a perfect example of this saturation. As more and more users share a particular node (e.g., a fiber optic node of the HFC network), the available shared bandwidth gets used up quite quickly. For example, a 3:00 pm slowdown phenomenon in residential neighborhoods, which occurs around the time when children come home from school, is apparent in most cable systems. Cable systems operate within a finite 850 Mhz bandwidth, and this limits the extent to which cable modem speed may be expanded without having to remove chunks of video programming content. Conventional cable systems are simply running out of room.
Accordingly, there is a need in the art for improved modem speed and reliability.